图例中错误栏的符号不透明度问题

Question

一旦我想在网格图中绘制线条和误差条的复杂组合，我就会尝试在图例中完美地指示符号。我注意到，当任何符号类型是错误栏时，为它们应用所需的不透明度并不容易。

我尝试检查此post但未成功。

import matplotlib.pyplot as plt
from matplotlib.collections import PathCollection
from matplotlib.legend_handler import HandlerPathCollection, HandlerLine2D, HandlerErrorbar


x1 = np.linspace(0,1,8)
y1 = np.random.rand(8)

# Compute prediction intervals
sum_of_squares_mid = np.sum((x1 - y1) ** 2)
std_mid            = np.sqrt(1 / (len(x1) - 2) * sum_of_squares_mid)

# Plot the prediction intervals
y_err_mid = np.vstack([std_mid, std_mid]) * 1.96

plt.plot(x1, y1, 'bo', label='label', marker=r"$\clubsuit$",  alpha=0.2)                                                 # Default alpha is 1.0.
plt.errorbar(x1, y1, yerr=y_err_mid, fmt="o", ecolor="#FF0009", capsize=3, color="#FF0009", label="Errorbar", alpha=.1)  # Default alpha is 1.0.


def update(handle, orig):
    handle.update_from(orig)
    handle.set_alpha(1)

plt.legend(handler_map={PathCollection : HandlerPathCollection(update_func = update),
                            plt.Line2D : HandlerLine2D(        update_func = update),
                          plt.errorbar : HandlerErrorbar(      update_func = update) # I added this but it deos not apply alpha=1 only for errobar symbol in legend
                        })

plt.show()

我目前的输出：

Answer 1

看来您没有为第二个

Artist

（即

ErrorbarContainer

）指定正确的处理程序，因此未针对该对象执行

set_alpha(1)

指令。

确实导入

import matplotlib.pyplot as plt
from matplotlib.container import ErrorbarContainer
from matplotlib.legend_handler import HandlerLine2D, HandlerErrorbar

然后将

handler_map

修改为

def update(handle, orig):
    handle.update_from(orig)
    handle.set_alpha(1)

leg = plt.legend(handler_map={
    plt.Line2D : HandlerLine2D(update_func = update),
    ErrorbarContainer: HandlerErrorbar(update_func = update)
                        })

结果

希望这有帮助！